1. Field of the Invention
This invention relates to air inlet assemblies for fan units which utilize sound absorbing material to reduce fan noise, as well as evenly distribute the flow of air to the moving fan blades.
2. Background Art
The use of sound absorbing material has long been recognized as an effective means for reducing noise created by operating fans. Sound absorbing material has been placed through slots in duct walls, thus openly exposing the material to the fan blades. U.S. Pat. No. 3,947,148 embodies an installation technique where the material is projected through openings in the duct walls so that a minimum distance exists between the tips of the fan blades and the sound absorbing material. However, the material is not contained and conserved within the structure. Sound absorbing material also has been enclosed in structures that expose the sound absorbing material to the "noise areas" of the fan. For instance, U.S. Pat. No. 3,762,497 describes the use of "sieve-like" walls along the air inlet area to increase the sound dampening effect of the sound absorbing material enclosed therein. This utilization is effective, since the holes in the wall directly expose the material to the "noise creating" area. U.S. Pat. No. 3,762,497 further describes this utilization as helpful in reducing the amount of space taken up by the sound absorbing material, as well as in making for an economically efficient sound absorbing device.
It is an object of this present invention to provide an air inlet assembly, further reducing the amount of space taken up by the sound absorbing material.
Another object of the present invention is to provide a very compact and contained air inlet assembly.
Still another object of the present invention is to provide an air inlet assembly utilizing readily obtainable strips of support structure and sound absorbing material.
It is a further object of this invention to provide an air inlet assembly which streamlines the incoming air and, at the same time, dampens fan noise.